During the last decades, a large number of scientific publications have described the genetic principles of coat colour and coat variation. Coat colours and coat variations are influenced by many hereditary factors. The DNA-tests are based on physiological effects in the body, in which the production and distribution of pigments result in many coat colour variants. In several cases, the coat colour of an animal may only be decided using DNA-tests.
The 20S proteasome ß2 subunit (PSMB7) gene is responsible for the Harlequin coat pattern in Great Danes. This gene is also known as H-Locus. Harlequin is a pattern resulting from interaction of the Merle (M-locus) gene and the Harlequin (H-locus) gene on black pigment. The Harlequin gene can modify the Merle gene. The Harlequin pattern is only expressed if on the M-locus at least one copy of the M allele is present in combination with at least one copy of the E or Em allele on the E-locus. Dogs that are not merle, or only have red pigment, cannot express the Harlequin gene. The dominant Merle gene, by itself produces dark spots on a diluted background. If a Merle dog also inherits one copy of the Harlequin gene, the dark spots increase in size and the background pigment is removed (turns white). The Harlequin mutation in Great Danes is in homozygous state (two copies of the mutation) considered embryonic lethal as no live dogs with two copies of the mutation have been observed. This means that pups that are homozygous for the Harlequin mutation do not develop in the uterus and are reabsorbed very early in the development process. Therefore all Harlequin patterned dogs have only 1 copy of the Harlequin mutation. The Coat colour H-locus (Harlequin) test (H316) tests for the genetic status of the H-locus. This gene has two variants (alleles), H and N. The allele H is dominant. One copy of the H allele, together with at least one copy of both the M allele for the M-locus and the E allele for the E-locus results in dogs with the Harlequin pattern. Two copies of the H allele result in early embryonic death. The allele N does have no effect on the coat colour.
Test specific information
Since 2015, two brands have been developed. CombiGen®
is mainly directed at veterinarian applications, whereas CombiBreed®
is mainly directed at breeders and/or owners.
Detailed information about Coat Colours and Coat Variation is presented at www.combibreed.com.
Symptoms will develop at a young age. Within a few hours to a maximum of several weeks after birth, the characteristics that go with these genetic effects will become visible.
Turn Around Time
The turn-around-time of a test depends to a large extent on the logistics of sample transportation to the laboratory. After receiving the sample at the test location, you can normally expect the result within 10 working days. A longer delivery time applies to tests carried out by a Partner Lab.
Location of disease or trait
Genetic factors influencing coat colours and coat types are usually visible on the outside of an individual. Several factors may be hidden by the external variation.
This DNA test is available for the following breeds: Great Dane. Additional information is available in the Frequently Asked Questions (FAQ).
For this DNA test we accept the following materials: Blood EDTA, Blood Heparin, Semen, Swab, Tissue. Please contact Dr. Van Haeringen Laboratorium if you wish to submit other material as listed.
This genetic factor is inherited in an autosomal, dominant, mode. This means, that the individual can be free of the mutation (homozygote normal), affected (homozygous affected) or carrier (heterozygous affected). Both carriers and affected individuals will show symptoms of the mutation.
Severity of Disease
Factors influencing coat colour and coat types are usually not related to diseases.